The invention relates to a device for introducing an anchor element, in which a thread is engaged, into a bone in order to fix a tissue that is detached from the bone, with an elongate body whose distal end is designed in such a way that it can be connected to the anchor element in a rotationally locked manner.
A device used for introducing an anchor element, and having these structural features, is known from the company catalog produced by Karl Storz GmbH & Co. K G, Tuttlingen, “STORZ, DIE WELT DER ENDOSKOPIE, ARTHROSKOPIE, SPORT-MEDIZIN, WIRBELSÄULENCHIRURGIE” [STORZ, THE WORLD OF ENDOSCOPY, ARTHROSCOPY, SPORTS MEDICINE AND SPINAL SURGERY], 2nd edition January 2005, page 114 (equipment No. 28179 TI).
Such devices are used to introduce an anchor element, in which a thread is engaged, into a bone, such that the anchor element is anchored in the bone. Both ends of the thread engaged in the anchor element are tied to a torn tendon or a torn ligament, in order to fix these once again to the bone. A main area of application of such anchor elements is in the fixing of torn tendons in the shoulder region.
The device mentioned at the outset comprises an elongate body, which has a grip arranged at its proximal end. A distal end of the body is provided with a projection that can be introduced into an opening in the anchor element. The distal projection is designed in such a way that the device can be connected to the anchor element in a rotationally locked manner. The device known from the Storz catalog also comprises a lateral binding device for the thread that is threaded through the anchor element. For driving the anchor element into the bone, the two ends of the thread threaded through the anchor element are guided along the body and then wound round the radially protruding binding device.
The introduction of the anchor element into the bone by means of the abovementioned device can be done by two procedures, depending on which anchor element is used.
In the first procedure, a channel is drilled in the bone, and an anchor element is introduced into this drilled channel. For this purpose, the anchor element is fitted onto the distal projection of the device and turned into the bore. After the anchor element is in place, the device is removed, and the tendon is fixed to the bone with the thread ends. To ensure that the anchor element anchors itself in the bore, hook-like or barb-like projections are present on its outer face.
In a second procedure, the tip of the projection of the device extends beyond the distal end of the anchor element, the outer face of which is provided with a screwthread. By impaction and then a rotation movement of the device connected to the anchor element in a rotationally locked manner, the anchor element can dig into the bone and thereby be anchored. Thus, an anchor element of this kind can be fitted without first preparing a bore.
Irrespective of which type of anchor element is used, the ends of the thread threaded through the anchor element, which ends are wound up on the lateral binding device during introduction of the anchor element into the bone, are released from the binding device after the anchor element is inserted into the bone. Before the torn tendon is tied to the two ends of the thread, the two thread ends have to be separated arthroscopically one after the other, which is extremely complicated and requires a great deal of skill, even on the part of an experienced surgeon.
An operating technique has now been developed in which the thread is passed from one side through the transverse opening in the anchor, is curved on the other side to form a loop, and is guided back again in the opposite direction through the transverse bore.
Thus, a loop of the thread protrudes from one side of the anchor element, and two free thread ends on the opposite side.
When the device mentioned at the outset was used with such a thread configuration in the anchor element, difficulties arose in fixing the loop to the screwing-in device.
European patent application EP 1 484 022 A2 discloses an insertion tool for inserting a plurality of suture anchors having at least one locking wing extending radially from the shaft of the anchor. The insertion tool includes an S-shaped slot configured to permit the insertion tool to insert a plurality of suture anchors. The S-shaped slot includes a distal portion appropriately dimensioned for loosely receiving a radially extending wing of suture anchor. An angularly offset proximal portion is configured to receive suture threads, a proximal portion forming a suture guide hub.
International patent application WO 2004/062507 A2 discloses a device for introducing an anchor element having an elongated body whose distal end is designed in such a way that it can be connected to the anchor element in a rotationally locked manner. Within the distal end which is inserted into the hollow body of the anchor element there is provided a gap for receiving a loop of the thread located within the anchor element.
It is an object of the invention to develop a device of the type mentioned at the outset, for introducing an anchor element into a bone, in such a way that, together with a simple construction, the thread is held securely during introduction and can be easily separated thereafter.